Evidences for the involvement of the Galectin-1 in the interaction of pig chondrocytes with a lactose-modified chitosan, namely
Chitlac, are reported. The Chitlac glycopolymer has been shown to promote pig chondrocyte aggregation and to induce extracellular
matrix production. Highly pure Galectin-1 was obtained from pig spleen by affinity chromatography and its identity was determined
by ion spray mass spectrometry analysis of tryptic peptide fragments obtained after in-gel digestion. The complete sequence of pig
Galectin-1 CDS was obtainedby screening a pig EST database using human Galectin-1 sequence as template. The Galectin-1 cDNA
was clonedinto a pGEX-4T-1 expression vector andthe recombinant protein was purified, characterizedandusedto produce a
rabbit anti-serum. Recombinant Galectin-1 interacts in a dose-dependent manner with Chitlac as determined with ELISA assay.
Expression level of galectin-1 gene, quantifiedby real-time PCR, was significantly higher in chondrocytes cultivatedon Chitlac. In
the same way, the presence of Chitlac stimulates secretion of Galectin-1 in culture medium that, by immunohistochemical analysis,
revealed to be clustered on the surface of Chitlac-induced aggregates. These data indicate the role of Galectin-1 as a bridging agent
between Chitlac andchond rocyte aggregates.
